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•ฃ20                        METALLURGY OF IRON AND STEEL. '
error* in .supposing that this ^reaction produces 'heat, it may .be ••well .to take; the data given by Mr. Talbot showing "the composition of 'the pig-iron and 'of the slags produced. It, will therefore be1 assumed that the pig-iron contains 1.00 per cent, of silicon and 3.75 per cent, 'of carbon., and one ton will be taken as a basis. It will also be assumed that the -ore is pure 'ferric oxide (Fe203) and the problem is to find how much ore is to be added. It is 'easy to calculate how mucli'oxygen is necessary to burn the silicon, but in ad-'dition to this a certain'amount of FeO will combine with the Si02 /to form'a slag, and the;rela'tive proportions of these two substance? depend upon many conditions. In the acid furnace it would not be far wrong to assume that equal weights would be called for, a condition roughly expressed by the formula 5 Si02 4 Feb. In the basic furnace the conditions a'r'e 'more complicated, but the relation of Si02 and FeO is about the same as in the acid slag. In the present case there is no need to theorize; we are discussing the use of oxide of iron in the Talbot process, and in the • description of this process the composition is given of thirteen different slags after the reaction with iron, oxide is completed. Taking the average, we have the following: '
Si02===12.75 per .cent.==5,95; .per cent. Si. Fe=15.13 per cent.                                              , *,,,.-•;.
.....         . .    '         .      '                              -    .          -       '         •      •    V      ..,....,,.                    .                 -    .          •: 4' f
'Thus when iron, oxide reacts upon,pig-iron, under the conditions related by Mr. Talbot,, the silica from the oxidation, of silicon and from .other sources enters the slag and carries ferrous,oxide witli .fit in such proportions that 5.95 kilos of silicon accompany .15.13.kilos of metallic iron,,, •.which is in the proportion of 10 kilos Si'to ,$5.43 lulos-Fe. The relative weights will'follows-: V              •,. , <:
10 kilos Si==25.43 kilos Fe—32.69 kilos FeO=36.33 kilos Fe;(X
For every ton of pig-iron containing one per cent, or 10 kilos of silicon, the slag will, require 32.69 kilos of'ferrous oxide (FeO), while 36.33 kilos of ferric oxide (Fe208) must be added:to supply it:.
* For Mr. Talbot's views see Journal I. and S. I., 1900, p. 38. I quota two representative passages: '" And thus facilitates rapid'chemical action, Tby which more heat is produced." "It will be seenthat both the reducing and heat'giving power of these congtit-uents is not a mere piece of theory, but a practical fact." It may be noted that Mr. Berbrand at Klando recognizes the great cooling effect of ore reactions.                        ;